Patent GB-1499000-A (GB)
Title: Wheel balancer
IPC: G01M1/22
Filed: 1975-12-15
Abstract: 1499000 Dynamic wheel balancers; measuring wheel unbalance electrically YAMADA YUKI SEIZO CO Ltd 15 Dec 1975 [23 Dec 1974] 28 Feb 1975 (2) 4 March 1975] 51338/75 Headings G1N and G1X A wheel balancer comprises a rotary shaft 32 and two support shafts 19 held by respective spring members 21 on each side of the rotary shaft and supporting the rotary shaft via a plate 28 to provide a centre of vibration K 1  for a wheel 61 under test, the support shafts lying on a circle centre K 1  the centre K  1  being movable along the  centre axis of the rotary shaft and each support shaft being movable, in response to vibration of the wheel and rotary shaft, in direction tangentially of the circle whereby unbalance is measured by the amount of vibration. The rotary shaft 32 is mounted in bearings 31 secured to the plate 28 which is secured at its ends to bearings 26 holding the support shafts 19 at one end thereof; the other ends of the shafts 19 being fastened to a respective elastic body 18 having grooves 20 to define the spring members 21, the latter being secured via bolts 23 to a body 5 secured to a base-plate 1. The elastic bodies 18 and support shafts 19 are rotatable together by means of a handle 11 and gear 10 to adjust the position of the centre of vibration K 1 , i.e. from one side of the wheel to the other. Vibration of the shaft is detected by a Piezo-electric element 42, the amplitude and phase of the output being utilized to determine the size and position of correcting masses to be applied to the wheel. The Piezo alternating output is fed through amplifiers (100, 101 and 109), Fig. 20 (not shown), variable resistors (102, 105) adjustable to the thickness and diameter of the wheel, switch (104) for use when changing the centre of vibration from one side of the wheel to the other and a Schmidt circuit (112). The Schmidt output is connected through a differentiation circuit (118) and a switch (144) to a positive clipper circuit (119), a flip-flop (120) and a comparison circuit (135), Fig. 21 (not shown). Difference in voltage across resistors (131, 133, Fig. 21) occuring at the set and reset conditions of the flipÀflop are shown at an indicator 134 and indicate the amount of unbalance; they are corrected by adjustment of variable resistors 107, 108. The maximum amplitude position of the Piezo signal represents the position of wheel-unbalance. A comparison of this position is made by rotation of a dial (49b) and notched plate (43) against a photoelectric cell (46) to produce a signal every revolution which is supplied to the input end (125) of the flip-flop (120). In use, with a wheel 61 mounted, resistors (102, 103) are set to the size of the wheel, the handle 11 is rotated to adjust the centre of vibration with the inside of the rim as indicated by a pointer 47. Switch 106 is set to connect the variable resistor (107) and the wheel is rotated. A dial (92) is rotated to adjust resistor (107) for a zero deflection at the indicator (134) of the comparison circuit (135). Phase detecting switch (122) is then changed and the dial (49a) rotated for zero deflection at the indicator (134). The positions of the dials (92, 49a) indicate the magnitude and position of weight to be applied to the wheel. The handle 11 is then set to place the centre of vibration on the outside rim of the wheel and the process is repeated.